Separable insulated connectors provide an electric connection between components of an electric power system. More specifically, separable insulated connectors often connect sources of energy—such as cables carrying electricity generated by a power plant—to energy distribution systems or components thereof, such as switchgears and transformers. Other types of separable insulated connectors can connect to other separable insulated connectors on one or both of their ends.
Depending on the type and function of a separable insulated connector, the connector can include a variety of different interfaces. For example, many separable insulated connectors include two interfaces, one at each end of the connector. Some separable insulated connectors can include one male interface and one female interface, two male interfaces, or two female interfaces.
An exemplary connector with two female interfaces can, for example, include a bus bar—or conductive member that carries current—connecting the two female interfaces. Each female interface can include a “cup” through which one end of a probe can be inserted and then connected to the bus bar disposed within the separable insulated connector. The other end of the probe then can be connected to energy distribution components or other separable insulated connectors.
The cups are typically made from semi-conductive material and thus can serve as a faraday cage. As used throughout this application, a “semi-conductive” material can refer to rubber or any other type of material that carries current, and thus can include conductive materials. The purpose of a faraday cage is to shield all gaps of air within the mating components of the separable insulated connector, as these air gaps can cause corona discharge within the connector. This discharge can occur if there is a voltage drop across the air gaps, and the discharge can corrode the rubber materials often used to make the separable insulated connector. The faraday cage ensures that the various mating components have the same electric potential, and thus prevents corona discharge within the mating components.
Conventionally, the cups of such female-female separable insulated connectors are made from a rigid, conductive metal, such as copper. The cups, as well as the bus bar connecting them, are placed within a semi-conductive shell of the separable insulated connector. Conventional separable insulated connectors also can include various layers of insulating material—such as between the cups and the probes inserted therein, between the cups and the shell, and around the bus bar. The various layers of insulating material used in conventional separable insulated connectors can provide a barrier to shield the high voltage components from the exposed shell. Such a configuration can reduce or remove the risk of electric shock from touching the exterior of the separable insulated connectors.
This configuration of conventional separable insulated connectors has created several problems. Notably, it is difficult to bond the insulating material—which is generally made from a rubber such as ethylene propylene dienemonomer (EPDM) rubber, thermoplastic rubbers (TPRs), and/or silicone rubber—to the cups or the bus bar, both of which are generally made from metal. Rubber does not typically form a strong bond with metal. A strong bond between the insulating material and the metal cups and/or bus bar also is desirable because without a strong bond, air gaps can form between the metal and insulating materials. Corona or partial discharge can occur within the air gaps between the conductive metal and the semi-conductive rubber. The discharge can lead to severe damage of the insulating material and the connector. Manufacturers of conventional separable insulated connectors often coat the bus bar and/or cups with an adhesive to enhance the bond with the insulating material. However, in addition to creating an expensive extra step in the manufacturing process, these adhesives can be toxic and can cause environmental problems during storage, manufacturing, and disposal.
An additional problem created by the conventional configuration of such separable insulated connectors also stems from having insulating material bordering the bus bar. In such a configuration, the surfaces, edges, and corners of the bus bar must be smoothed and/or softened to remove any burrs, other irregularities, or sharp corners that may be present on the bar. Absent this step, such items on the bus bar can cause stress to or otherwise damage the insulating material that surrounds the bus bar, given the difference in electric potential between the bus bar and the insulating material, thereby causing damage to the entire separable insulated connector. Thus, manufacturers of conventional bus bars must perform the time consuming, labor-intensive, and expensive process of smoothing the bus bars prior to applying the insulating material.
Yet another problem with conventional separable insulated connectors is the tendency for conventional faraday cages to disconnect from the bus bar. The connection between conventional faraday cages and bus bars can become loosened during the manufacturing process, especially when insulating material is injected or otherwise inserted between the faraday cage and the shell. If the connection between the bus bar and the faraday cage is dropped, the faraday cage may no longer have the same electric potential as the bus bar, which therefore defeats the purpose of the faraday cage.
Thus, a need in the art exists for a separable insulated connector in an electric power system that addresses the disadvantages found in the prior art. Specifically, a need in the art exists for a dual interface separable insulated connector that does not require insulating material to bond to the bus bar. A need in the art also exists for a dual interface separable insulated connector with a faraday cage that can bond to insulating material without the use of an adhesive material, if desired. Yet another need in the art exists for a dual interface separable insulated connector with a faraday cage—and a method of manufacturing the same—where the connection between the faraday cage and bus bar is stronger and less likely to disconnect.